Fluid operated engine for downwell pumps



5 Sheets-Sheet l R. H. DEITRICKSON FLUID OPERATED ENGINE FOR DOWNWELL PUMPS /QTTORNE YS x x Y. i x. x

x A k E 2 xxx.;

June 29, 1954 Filed July 7, 1952 June 29, 1954 R. H, DEITRICKSON 2,682,257

FLUID OPERATED ENGINE FOR DowNwELL PUMPS Filed July 7, 1952 s sheets-sheet 2 1% 152 i 439 i r 43 -m /N V/VTOR /08 EVN/09 June 29, 1954 R. H. DEITRlcKsoN 2,682,257

FLUID OPERATED ENGINE FOR DowNwELL PUMPS Filed July 7, 1952 5 sheets-sheet s XX x Y A x June 29, 1954 R. H. DEITRlcKsoN 2,682,257

FLUID OPERATED ENGINE FOR DOWNWELL PUMPS Filed July 7, .1952 5 Sheets-Sheet 4 TABLE- 2 ANNuLus N? INVENTR.

Fl 8. Rdy'fl Defr/'c/fson 'g BY @mu @ak June 29, 1954 R. H. DElTRlcKsoN FLUID OPERATED ENGINE FOR DOWNWELL PUMPS 5 Sheets-Shee-t 5 Filed July '7, 1952 Figi?.

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ATTORNEYS Patented June 29, 195.4

UNITED STATES PATENT OFFICE FLUInpPERATEDENGINE Fon DoWNWELL PUMPS Roy H. Deitrickson, Toledo, Ohio, assigner to The National -Supply v Company, Pittsburgh, Pa., a corporation of Pennsylvania Application July 7, 1952, Serial No.l 297,473

17' Claims. 1 t

This invention relates to a uid operated engine for a downwell pump. A pump of this class is positioned at or near the bottom of a deep well tubing for pumping uid from a relatively great depth and is operated by working uid, under pressure originating in equipment on the surface of the ground and conveyed to a fluid engine disposed in the tubing and `operatively connected to the pump. Since the pressure iiuid control valving in the iiuid engine must operate with great regularity over long periods of time, it must be highly positive in its` action land must bev so arranged that collection of sand and the like in the associated pump cannot cause operation to stop.

In general, pumps of this, character have been designed so that the stroking motion of the engine piston is relied on to cause reversal of the engine piston, either by reason of piston-carried valves overrunning certain ports, or by reason of the piston making contact with certain valve operating rods. In none of the prior devices with which I am familiar is hydraulic pressure alone utilized to cause shifting of the valve parts. The present invention has for its primary `object the provision of means to take advantage of' certain changes of pressure of motive fluid to cause reversal of movement of the engine piston by shifting the control valving. The fluid engine of the present invention thus makes it possible to utilize identical valving-'for operatingpumps having many different lengths of stroke. The valving may thus be conveniently madeas a short uni" tov be attached to thev top .of an engine cylinder.

It has also been generally proposed to make the control valving as an extension of the engine piston so that the valving functions whenvit is carried over certain ports at the top and bottom of the engine piston stroke. The valves thus are required to fit very closely against the stal duces the number and extent of the surfaces requiring highly accurate machine work.

In many of the pumps previouslyl available the assembly has been so complex that servicing in the field has been virtually impossible and the practice has been to substitute a new unit for the defective one whenever pumping stopped for reasons clearly attributable to the pump. The defective pump has usually been taken to the original manufacturer `for repair. One of the objects of the present invention is to so simplify the construction and assembly of the parts thatl repairs may be made in the eld Without the use of specialized equipment.

It is yet another object of this invention to provide a valving mechanism for an hydraulically epera-ted downwell pump in which a control clement is so designed as to be biased toward a position effectuating movement of the valving in one direction by reason of hydraulic differentials acting on the control element and to remove the biasing force of the control element from the valving and permit the establishment of a force on the valving to provide for movement of the valving in the opposite direction appropriateto accomplish a reversal of the valving connections and consequently of the direction of movement of the engine and the pump pistons.

Itis a still further object of this invention to provide a valving mechanism so integrated with the reciprocatory movement of the pump engine piston that reversals i. e., changes in direction-of movement of ,the engine piston at its stroke extremities, are caused by hydraulic pressure inresponse to the approach of the engine piston vto the extremities of its stroke, whereby even under adverse operating conditions such as the presence of a gas pocket, the engine piston will not be driven forcefully against the ends of the cylinder in- Which it reciprocates.

Yet another object of this invention is to provide a control element for the valving system of anl hydraulically operated downwell pump in which the control element anticipates the need for changes inthe position of the valving, i. e., the connection or release of power fluidto the engine piston, by responding to changes in the pressure of exhaust fluid from the engine piston.

Another important object of this invention is the provision of a control element in the valving system of an hydraulically actuated downwell pump which acts as a governor for the speed of operation of the engine cylinder and, therefore, the strokes per minute of the pump, preventing the occurrence of excessively high speed or rac- 3 ing strokes which might damage the pump, engine or valving mechanism.

Other objects and advantages of the present invention will become apparent from the following detailed description of the construction and operation of a preferred form of the invention, reference being had to the accompanying drawings in which:

Fig. 1 is a vertical sectional view of the upper end and in particular of the valve `rchamber of an hydraulically operated downwell pump embodying the invention, showing the valve mechanism in the position assumed during the downstroke of the pump engine and the associated pumping piston.

Fig. 2 is a view similar to Fig. l and is a continuation thereof with a small overlapping portion at the upper end of Fig. 2 and the lower end of Fig. 1, and shows the engine cylinder portion of a downwell pump embodying the invention, i. e., that section of the pump next below that shown in Fig. 1.

Fig. 3 is a view similar to Figs. 1 and 2 but of the lowermost portion of a pump embodying the invention and illustrating the production fluid pumping cylinder, being, in turn, a continuation of Fig. 2 and showing the next lower section of a pump embodying the invention.

Fig. 4 is a View similar to Fig. 1 but showing the location of the valving mechanism at the bottom reversal of the engine piston and pump plunger.

Fig. 5 is a view similar to Figs. 1 and 4 but illustrating the positions of the valving mechanism during an upstroke of the engine piston and the pump plunger.

Fig. 6 is a view similar to Figs. 1, 4 and 5 but illustrating the position of the valving mechanism at the top reversal of the engine piston and pump plunger.

Fig. 7 is a somewhat diagrammatic vertical sectional view corresponding to Fig. 1 but with the diameters of the parts and the differences in diameters exaggerated and their lengths diminished to illustrate balancing pressure differentials existing during the downstroke of the engine and pump pistons as also shown in Fig. 1.

Fig. 8 is a view similar to Fig. 7 but showing the position of the valving mechanism at that point in the cycle of operations shown in Fig. 5, i. e.,

In describing the structure of a pump embodying the invention as illustrated in the drawings the consideration of the pump will be divided into three mechanical sections, viz., the production fluid pump (Fig. 3), the pump engine (Fig. 2), and the control valve mechanism (Figs. 1 and 4 8, inclusive).

In describing the operation of a pump embodying the invention the operation of the production fluid pump will be set forth following its mechanical description and the operation of the engine will be set forth following its mechanical description. The operation of the valving mechanism will, in turn, be broken down into adescription of the operation of the valving mechanism during the downstroke (Figs. 1 and 7) its operation at bottom reversal (Fig. 4); its operation during the upstroke (Figs. 5 and 8) its operation at the time of top reversal (Fig. 6) and the overall control of the pump by means of which certain elements of the mechanism cooperate to govern the speed of operation and to prevent undesirable racing strokes from taking place when gas enters the pump or when other changes in operating conditions occur.

The rst section of a device embodying the invention is the pump itself which may be of any suitable form. In Fig. 3 a well tubing 20 having a pump seat and packer fitting 2l is shown as extending downwardly into the production area of a well. The pump consists of a tubular pump cylinder 22 which is concentric with the well tubing 20 and which is seated on the packer 2 I. At the end of the pump cylinder there is a cylindrical valve chamber 24 that connects with an axial intake opening 25. For fitting the parts together, the lower end `of the pump cylinder 22 may be turned down to form a cone end 26 which seats in an axial cone socket 21 in the packer 2l.

A pump piston 28 is located in the interior of the cylinder 22 yand is secured on the lower end of a piston rod 29 which extends axially into the cylinder 22 through a coaxial bore 3S in a connector 3| which is functionally integral with the pump cylinder 22. The pump piston 28 is axially bored to form a duct 32 that is connected by a plurality of circumferentially spaced passageways 33 with a space 34 at the top of the pump cylinder above the piston 28. At the lower end of the piston 28 its central duct 32 is enlarged to form a valve chamber 35 with a cone seat 3S at its lower end. A travelling valve in the form of a ball check 31 rests on the cone seat 36 during the upward strokes of the pump piston 28 but moves away from its seat into the chamber 35 during the down stroke of the pump piston to permit the passage of production fluid.

A standing valve located at the lower end of the valve chamber 24 consists in a ball 38 and a seat 39 which is formed in the packer fitting between the valve chamber 24 and intake opening 25. The interior of the pump cylinder is connected through a group of radially extending openings 40 to a production fluid conduit 4I formed by the annular space surrounding the pump cylinder 22 between its walls and the walls of the well tubing 20.

PUIWP OPERATION The pump section of the modiiication of the invention illustrated in the drawings is a single action pump. As will appear when the operation of the engine and valve sections ofthe device are described, any type of reciprocatory pump may be employed and the choice of a single action pump as illustrative is not a limitation on the scope or construction of embodiments of the invention. When the pump piston 28 is moved upwardly during an intake stroke, the standing valve ball 38 is lifted from its seat 39 and production fluid flows inwardly through the intake opening 25 filling the pump cylinder 22 beneath the piston 28 at its rises.

After the piston 28 has reached the top of its stroke, its direction of movement is reversed and it starts down. This action applies pressure on the oil located in the cylinder 22 beneath the piston 28 which seats the standing valve ball 38 in its seat 39 preventing the escape of production fluid in the cylinder 22 out of the intake opening 25. This same movement of the piston 28 unseats the travelling valve 31 from its seat 36 and the downward stroke of the piston 28 thus consists in a movement of the piston 28 through the body of iluid in its cylinder 22, in effect movine. theuid through the. duet 32:. from beneath the piston 28 to; above-the .piston 2.8.;.1

After the piston ,1.28.- hasmoved to. the..bottom of its cylinder 22.. andrstartsupwardly again, the travelling ball `valve 3l. is seatedandallf-of the iluid. lwhich has been i transferred. into the` space 34 above the piston 28,..v ismoved outthrough the radial openings 4U into the annular production fluid discharge` conduit .4t surrounding the connector 3|.

The reciprocation of the pump .piston28 fills the cylinder22 on one upstroke,.and at the same time discharges the .production uid transferred to thespace Vabovethe piston-.lvwhich was drawn into the pump `during a .previous .upstroke. l

PUMP ENGINE.

The` second sectionof a device .embodying the invention consists in lthe. vengine,,section which is shown in Fig. In the enginedsectionpfthe device the connector 3| to which the.. pump cylinder 22 is attached at the bottom, .is constructed to receive two concentric spacedV tubes. forming an engine casing, 42 and an engine cylinder 43. The exterior engine casing.. 42 is; spaced fr0m the interior of the .well tubing 20.110 formacontinuation ofthe annular production vfluid' conduit 4|. The inner engine cylinder43 is yconcentric with and spaced. inward-lygfromthe engine casing 42, thus formingl .a second. annular conduit 44 which extends along the entire lengthA of the en.- gine cylidner. 43 for `the, Apurpose of introducing power uid into the interior ofthe enginecylinder 43 near the lower end thereof. The annular conduit 44 communicatesthrough La plurality `of radial openings 45 with the interior ofthe en gine cylinder 43./ The ,upper end of the` piston rod 29 extends coaxially into theicylinder- 43 -from the bore 30 in the connector fitting 3|., The, engine cylinder is of the. same diameter throughout ite length except` fera .redueedelameter sump 41 that is located just abovethe radialpQWer .fluid openings et the hettem'fozf the. .engine cylinder 43 andan. upper. reduced .diameter pocket 48 at. the upper .end of. theengine cylinder .43..`

An eneinepisten. 48. havinga .suitably Ipacked and elongated main body section 5B slidingly; lits the interior diameterei the. engine evlinder. `43 and, reepreeatesihereim The. pist-.cured .29 is operatively `connected. to the .lower -end ofthe piston 49 and V.has an enlargedsection 5|V at` its upper end which .has anoutside .diameter loosely tting the interior diametero the cylindrical Sump 4l et the bettomrof, the .engine ,cylinder 43- The piston rod sectionl has anaxial `length equal to the axialleneth ofA thesunippfl` above the radial power fluid inlet openings 45H.:l

At the upper end of the enginepistonl acylindrical extension 52, oi'y reduced diameterextends axially ,from` the main body 5l)` of thepiston 49. The extension52 `hasan `outside,diameter which slidingly fits. into the interiorv ,of-the pocket 48 ofthe cylinder 43'.l Thelengthofthe extension `52 isless than the axiallength of .ther pocket 48. Anl annular shoulder 53 stepsthe-.outer ,diameter o the piston body down to that. of ythe extension 52.

ENGINE PISTON OPERATIQN- It will be observed `in Fig` v21 that the operating area ofthe upper endof the engine piston 43 is. the total ofthe areaoftheend ofthe extension 52 and the annularV shoulder. 53, i. e., the entire cross sectional area of the pistonbody 50i.,l The..

effective. operating. area. of the lower end of the piston 49 isthe diierence between the area of the main. body andthe cross sectionaly area of the pistonrodli.` 'Ilhus.theeffectivetop-area of the piston 4.9/` is substantially greater than the effective bottom area` of the piston-49g.. Therefore, if Working iluid at the same-.pressure .is admitted simultaneously above .andnbelow the piston 49, the piston will mov :-.downwardly. This is, in fact, the way in which the engine piston 491s moved to effect a downstroke and, through the connectingv piston `rod 29, a downstroke of the pump piston 28.

Upwardstrokes of.V the engine piston V49 and thus` ofthe pump piston 28 .are achieved by the pressure diiferentialbetween the iluid above and below the piston 49 rather than by an area differential. When the pistonv49 is to be moved upwardly the interior of lthe engine cylinder 43 above` the piston 49l-is vented,..through valving means to be described below, either` to the productionfluid discharging conduit 4| or, if y desired, to a separatev power iluid exhaustline. Power fluid under the same working pressure is still connectedhowever, through the inlet openings 45. and thus applies a constant high pressure on the lower end of the piston A49` to drive the piston 49- upwardly expelling the spent working fluid` located above the piston 49` to the discharge as mentioned.

The presence of high pressure power ilud in the engine cylinder beneath the piston 49 at all times, i. e., both during up and down strokes, simplies ther valving in .a do'wnwell pump embodying the invention ,by eliminating any necessity for alternately charging and venting the lower end of the enginel cylinder 43.- Presence at all times of high pressure power fluid beneath the piston 49' also provides for the escape of a slight ilm of this fluid around the piston 49between its exteriorsurface and the interior of `its cylinder 3 for `the` purpose oflubricatingthe piston 49. This` same thinlm -of-power uid may also escape around the piston rod V29 where it passes through the bore 3D inthe connector 3| between the pump and engine portions ofthe device. The cleaning :dow of power fluid around the piston rod 29. .effectively prevents the ingress ofany production uid or solids carried thereby. into the -intet rior ofthe engine cylinder 43.

vALvEMEcHANiSr/f.

The general construction of the valve mechanis'msection of a downwell pump embodying the invention is shown in Fig. 1 and` Figs, 4-8, inclusive. Agcom'parison of Figs. l and 2`wil1 show that a portion of the upper end of the engine casing. 42 and .engine cylinder 43I is shown in both figures. At the upper end of the reduced diameter pocket 43 there is an axial bore 54 through which extends the lower end of a tubular valve stem 55.. A series `of longitudinally extending passageways 56 are drilled through the walls of the cylinder 43v around .the pocket-48 .connecting the interior ofvthe cylinder 43 above the piston 49.with a lower pocket 51 in a flow chamber 58 located at. the lower endof .the Valve section of al pump embodying. the invention. The lower ends. of the passageways 5S allterminateat an annular Jshoulder 59 `extending..between the reduced diameter pocket. |81y .of the engine cylinder 43 and the main wall of the enginecylindei` 43. Thel lower. endsv ofthe passageways 56.. .thus areA in line. .with,the annular shouldertgon the ,engine piston.49\..I

The valve stem 55 is operatively integral with a sliding valve body generally indicated at 60 which has a varying external contour Hformed by shoulders and seats and different external diameters. The valve body 60 has an axial bore 6| extending from the lowermost end of the Valve stem 55 through the body 60 to its upper end and terminating in a group of angularly directed circumferentially spaced orices 82 which surround a stem S3 of a valve head 64.

The valve mechanismoperates within a generally tubular valve casing 85 spaced inwardly from the well tubing 20, the annular space therebetween being a continuation of the production fluid conduit 4|. The valve casing 55 is structurally a continuation of the engine casing 42 and surrounds the upper end of the engine cylinder 43 which is tapered as at 56 and which terminates in a ilat annular Vlip 81 lying in a plane perpendicular to the axis of the mechanism.

Just above the pocket 51 the upper end of the engine cylinder 43 (interiorly of the taper 66) is counterbored to form a slightly enlarged chamber 88 which surrounds the valve stem 55. The chamber 68 has an internal diameter that is a close sliding nt with a larger cylindrical portion G9 of the valve body 60. Axial slots 10 are milled through the shoulder' between the stem 55 and the valve portion 69 of the valve body 60 to provide for the axial passage of fluid from chamber t8 when the valve 69 is opened,

Immediately above the cylindrical portion 09 of the valve body |50, the diameter of the valve body 58 is reduced forming a short cylindrical section 1| on which a control collar 12 is slidably mounted. At its lower end the collar 12 has a radially extending annular shoulder 13 which, in certain positions, abuts against an opposed annular shoulder 14 formed by the enlarged cylindrical section 65| of the valve body G0.

The collar 12 has an enlarged diameter cylindrical rim 15 at its lower end. The outside diameter of the rim 15 is slightly smaller than the inside diameter oi' a land 16 formed on the inner surface of the valve casing 65 at the upper side of a conical wall 11 and just below a cylindrical wall 18 which has an internal diameter substantially larger than that of the exterior of any portion of the collar 12.

Just above the cylindrical section 1| of the valve body 88, an annular groove 19 is cut in its outer surface, The annular groove 19 is associated with and overlappingly mates a similar groove 80 cut in the inner surface of the collar 12. Above the annular grooves 19 and 80 the valve body 60 has a cylindrical section 8| having a diameter less than that of the cylindrical section 1| of the valve body 60. The inner bore of the collar 12 has a mating reduced diameter portion 82 which ts and slides on the reduced diameter section 8| of the valve body 60.

Because of this difference in the diameters of the two sections 1| and 8| of the valve body, the effective area at the lower end of the collar 12 is less than the effective area of the upper end 83 of the collar 12. This results in a pressure differential between the two ends of the collar 12 tending to move the collar 12 downwardly into engagement with shoulder 14 when power iluid is present in the flow chamber 58 surrounding the collar 12 and acting with equal pressure upon both of its ends.

The annular grooves 19 and 80 are made necessary by the change in diameters of the valve body sections 1| and 8| and the corresponding change in the diameters of the two mating inner surfaces of the collar 12. Because relative movement between the collar 12 and valve body 60 is necessary, the change in diameter must be carried out over an axial distance suiiicient to permit such axial movement and, therefore, the annular grooves 19 and 80 have substantial axial length. v

Because high pressure power uid always is present in the flow chamber 58 surrounding the collar 12, some of such fluid leaks between the collar 12 and valve body 60 into the annular rgrooves 10 and 80. .Because of this and the fact that the volume of the chamber formed by the annular grooves 19 and 80 changes with axial movement of the control collar 12, fluid must be allowed to flow in and out of the space formed by the grooves 19 and 80. The grooves 19 and 80 are connected by a radial opening 84 to a conduit 85 extending along the axial bore 6| in the valve body 60 and communicating with a second radial opening 88 which leads to an exhaust chamber 81 at the upper end of the valve body 8D. The chamber 81 is connected by radial openings 88 with an annular exhaust duct 89 that is connected by large radial ports 90 with the production fluid conduit 4| surrounding the valve casing 65 and inside the well casing 20. The system comprisingthe radial ports 90, exhaust duct 88, chamber 81, conduit 85 and annular grooves 19 and 80 is constantly connected to the production fluid conduit 4| at low pressure. High pressure power iluid never enters this portion of the structure. If desired, ports 90 can be connected to a separate power oil return line leading to the suction side of a poweroil pump at the surface of the well. Y

The collar 12 has a beveled shoulder 9| on its upper end 83 which opposes a beveled shoulder 92 formed on' a lip 93 atthe upper end of the wall 18 and which thus delineates the upper end of the flow chamber 58 'within the wall 18. The innermost'diameter of the lip 93 is less than the outer diameter lof the main body of the collar 12, and the opposed shoulders 9| and 92 thus cooperate to restrict or open an annular variable orifice at the top of' the control collar flow chamber 58.

Above the collar 12` the valve body 60 again is reduced in diameter and extends through a neck inthe valve casing formed by a lower shoulder 95 of lesser diameter'and an upper shoulder 96 of greater diameter. Above the shoulders 95 and 96 the casing 65 is formed to provide a spool valve chamber 91. The chamber 91 has an upper neck similarlyr formed by stepped shoulders 98 of greater diameter and 99 of lesser diameter.

A main spool Valve |00 is formed or mounted on the valve body 60 and located within the spool valve chamber 91. The main spool valve has a lower' extension |0| cooperating with the shoulder 95 and a-'rnain' 'cylindrical surface |02 which has a close sliding nt with the cylindrical shoulder 96 when the 'spool valve |00 is in its lower position. A similar relationship exists between an upper extension |03 and the uppermost shoulder 99 and between the sliding valve surface |02- and the shoulder 98.

Between the extension |0| and main surface |02 the spool valve |00 has a beveled surface |04 which mateswith'a beveled seat |05 between the lower shoulders 95and 96. Similarly an upper beveled surface |06 on the spool valve |00 mates with a beveledseat |01-connecting the upper shoulders 98 and.99.

In 'those installationswhere the present invention is set as a Ixed pump', a power uidconnection 86 leads to radial ports |09 at the upper end of the valve casing 65 which'connectto an annular power fluid conduit IIil spaced outside the annular escape duct '89. A plurality of radial ports iII which extend intovthe interior of the casing 55 just above the lip 93, connect the lower end of the annular conduit 'Ifi withthe interior of the valve mechanism above'the collar chamber 54 and power fluid is thus constantly available at the lower side of the main valve and thus at the upper end of the flow chamber 58. An axial bleeder passageway II2 is drilled through the lip 53 between one of-the `ports III and the upper end. of the flow chamber 158'for iluid bleeding as will be later described.

The central bore 6I vofthe valve'body 60 communicates withthe main spool valve chamber 91 through one or more radial ports I I3 and with the `interior of the engine cylinder 43 above the piston 43 through its open end at thelower end of the valve stein 55 and through aA plurality ofvradial openings H4 throu'ghthe walls of the valve stein 55 just above its lower end.

Near the upper end of the Ivalvebody 66, a balancing piston I l5, whichV is provided with several packing rings I I6, is mountedonlor integral with the valve body 66 and movable within the chamber 81. The balancingpiston 'I| 5 is sealed by the packing rings H6 against the wall of the chamber because at certain points in the cycle of operations it acts as a movableV wall between low pressure iinid in the chamber 81 beneath the piston H and high pressure fluid in a chamber Hl above the pistonI I5. A'plurality of bleeder holes H8 and connectingslots IIB extend longitudinally through the balancing piston I'I5 and terminate justbelow a disk-like flange |26 on the valve body 66. The flange isspaced axially from the top'cf the'piston |I5.

Referring to Fig. 9, a ring I2| is mounted circumjacently to the iiange |20 and has a downwardly directed lower lip |22 which is axially of sufficient length to`span'the space between the lower surface of the flange I2'and the top of the piston i i5 and to bear against the upper surface of the balancing piston I5 for closing ofi the bleeder slots IIS. The ring|2| has an upper lip |23 which retains a coiled check sleeve spring |24 acting between'the ring `|2| and a downwardly directed shoulder |25 on a vcheck Sleeve |26. The outer diameter of the lower end of the check sleeve |25 is the same as the outer I'diam-- eter of the flange V|26 and has a lower lip |21 which abuts on the flange |26 'whenthe vcheck sleeve |26` is moved downwardly. The interior diameter of the check sleeve |26 closely fits a lower enlarged section I 28 of the valve head stem 63. The upper end of the check sleeve |26 is enlarged, forming a lip |29, the lcweredg'e of which forms the spring retaining shoulder |25. The inner upper corner of the-lip |29 is beveled to form a seat |36 for a mating' beveled corner 53| on the bottom of the valve'head 64.

' The chamber I I1 is abruptly reduced in diameter just above the upper lipfof the check sleeve |26 to form a shoulder |32 againstwhichthe top surface of the lip |29 would bear if the check sleeve |26 were moved upwardly a suicent distance. The `shoulder "|32idefines the edge 'of a reduced diameter valve head pocket |33-into which the valve head64`is' moved in it'suppermost position.

The diameter of lthe enlargedisection |28 ci?V the valve stem 63 is larger than the diameter of the valve stem 63 immediately beneath the valve head 64 and thus an annularspace |34 is 'provided beneath the level of the seat v|36 into which space orifices 52 open from the central bore 6| of the valve body 60.

A plurality of axial bleeder openings |35 are drilled through the flange |20 opening into the space beneath the ring I2I in line with the slots II9 sothat oil may be bled'from the chamber `I These openings are controlled by the check sleeve |26.

The spring |24 normally tends to `maintain the check sleeve |26 in 4open position, away from bleeder openings |35, but when'high pressure power fluid is present in the chamber If|`|, the spring |24 is compressed permitting the lower lip |21 of the check vsleeve |26 toenter the space within the check sleeve |26 Yand close the openings |35.

The annular production fluid' conduit' 4| extends upwardly beyond thetop -of the valve casing 65 and (in the embodiment illustrated in the drawings) communicates with the annulus |36 surrounding the `power fluid line threaded into the connection I 08 within' the well casing 20. The annulus |36 extends to the surface, serving to carry production fluid upwardly, and in the ernbodiment shown, also carrying used power fluid out of the device.

OPERATION DoWNsTRoKE Figs. l, 2, 3 and '7 illustrate the position of the several parts of adevice embodying the invention shortly after the commencement of the downstroke of the engine piston 49. This movement is caused by the pressure of the power vfluid. fed into the valve section of the device (Figs. l and '7) from the power fluid line |08 through the radial port |09 `down the powerfluid conduit II6 and through the radial ports III into the vinterior of the flow chamber 58. From this pointvthe power iluid flows upwardly into the valve chamber 91 and through'the radial" ports |I3 into the interior of the valvebody A6|] and through the axial bore 6I to the upper end of the engine cylinder 43. This power fluid exerts force on the upper end of the engine cylinder 43 tending to' drive the engine piston downwardly and, through the medium of the piston rod 29 to push the pump piston 28 toward the bottom of the pump cylinder 22.

During suchv downward movement of the piston 49, the lower end of the engine cylinder 43 (Fig. 2) also is connected to the power fluid line |08 through the following connecting means: from ther sump 4'|'at the lower end of the engine cylinder 43 through the radial openings 45 to the annular power fluid conduit'44, around the tapered upper end 66 of the cylinder 43 and to the flow chamber 58. moved downwardly, as explained above, because the effective area of its upper end is greater than the eifective area of its lower end by an amount corresponding to the cross sectional area'of the piston rod 29.

Therefore, even though the power iluid under pressure communicates directly with the portion of the engine cylinder 43' beneath the engine piston 49, the ow of power fluid in the lower end of the engine cylinder 43 and thus in the annular power fluid conduit 44 is upwardly, i. e., the huid is expelled from the bottom of the cylinder 43 by movement of the engine piston 49 The engine piston 45 is 11 1 downwardly. The power fluid located beneath the engine piston 49, is forced upwardly through the annular conduit 44 at a pressure higher than that of the power iiuid being fed through the radial ports Ill, spool valve chamber 91, radial ports H3 and axial bore 6| into the upper end of the engine cylinder 43. These two phases of the power fluid meet, as it were, above the rim of the collar 12. The power fluid being forced upwardly from the lower side of the engine cylinder 43 has a greater pressure than the power fluid above the rim 15, so that there is a pressure drop at the upper shoulder of the rim 15. This tends to hold the collar 12 in its upper position, as shown in Figs. 1 and 7, even though its greater top area normally would tend to urge the collar 12 downwardly as is explained above. The collar 12, therefore, floats with the annular opening around its rim 15 and between the shoulders of the rim 15 and the land 16 maintained open by the flow of power fluid being expelled from beneath the engine piston 49.

As the engine piston 49 is driven downwardly, the downward movement of the pump piston 2S (Fig. 3) forces the production fluid located in the cylinder 22 beneath the pump piston 28 upwardly through the duct 32 into the interior of the pump cylinder 22 above the pump piston 28. It might be noted at this point that although the pump shown in the drawings (e. g., Fig. 3) is of the type generally referred to as a single acting pump, the presence of the piston rod 28 above the pump piston 28 reduces the volume of the pump cylinder 22 proportionately as the piston 28 is driven downwardly and all of the production fiuid drawn into the pump cylinder 22 beneath the pump piston 28 on its previous upstroke cannot be accommodated in the cylinder 22 when the piston 28 is driven downwardly. Therefore, a proportional quantity corresponding to the difference in volume between the pump cylinder 22 with the piston 28 at the top and the cylinder 22 with the piston 28 at the bottom, is pumped out of the pump cylinder 22 during the downstroke of the piston 28. This production fluid passes out of the openings 4D and into the production fluid conduit, i. e., the external annulus between the well tubing and the engine casing 42 to the large annulus |36 at the upper end of the device and thence to the surface.

During the downstroke of the engine piston 49, while the power fluid forced from beneath the engine piston 49 is flowing upwardly past the rim 15 of the collar 12, it would seem that its action would be to drive the collar 12 upwardly rather than maintaining it in the oating condition described above. However, if the collar 12 were driven upwardly far enough its upper beveled shoulder 9| would contact the downwardly directed beveled shoulder 92 stopping the flow of the escaping power uid around and past the collar 12 except for that portion which might iiow through the bleeder passageway H2, as hereinafter described. If this occurred, the es cape of the power fluid from the engine cylinder 43 beneath the piston 49 would be substantially stopped. This would equalize the pressures on the upper and lower faces of the rim 15 and, because of its greater effective area at the top (by reason of the difference in diameters of the portions of the valve body 60 on which it slides) the collar 12 would then be moved downwardly until the pressures acting around it again were balanced.

During the downward stroke of the engine piston 49, the main valve consisting of the valve body and all of its operatively associated parts, is held upwardly in the position shown in Figs. 1 and 7 by a relative pressure balance which results from the difference in the pressures of the power fluid (PP) and the exhaust and production uid (PL) acting over unbalanced areas of the balancing piston H5, spool valve |00 and offset shoulders formed by the annular grooves 19 and 80 cut in the collar 12 and valve body 60, respectively.

Referring particularly to Fig. '1 and to Table I appearing below, the balance of pressure areas holding the valve in the upper position during -the downstroke of the engine piston is derived as follows. The area of the valve body S0 indicated by the diameter line A is balanced out throughout the length of the body 60 except for the areas of offset created by the annular grooves 19 in the body 60 and 80 in the collar 12. 'I'he areas, therefore, which must be considered in determining the balance of pressures acting on the valve body 60 are those indicated in Fig. 7 as annulus a (diameter D-A) annulus b (diameter D-A); annulus c (diameter C-A); annulus d (diameter C-A) annulus e (diameter A-B) and annulus (diameter A-B).

In the calculations for Table I below, diameter A of the main valve body 60, the diameter from which the respective balancing annuli are calculated, is based upon an actual embodiment of the invention and has a value of 0.750 inch. The other diameters, viz., B, C and D, have respective sizes in relationship thereto such that the annuli indicated by the letters a, b, c, d, e and f have the areas shown in Table I below. These particular dimensions and the areas effective at any time are included here merely by Way of example and, of course, change appropriately in pump engines having different dimensions.

Table I .-Pressure balance on, valve during downstroke (See Figs. l and 7) A 19111; F1 'd Efectiva D' mm ar ui rea 111 lreelus Num- Acting Sq. tion Balance ber Inches 115 High.. .2953 Down 115 Low-- .2953 Up+ .2953 (Pp-PL) Low- 2485 Down 100 High.. 2485 Up -I- +2485 (PP-PL) 101 High., 0706 Up 79 Low.- .0706 Down +0706 (PP-PL) -1-.0238 (PP-PL) Pp=Power or high pressure fluid. PL=Exhaust or low pressure iiuld. (PP-PL) Pressure dilerentlal.

Fig. 7 illustrates the position of the valve body 60 and its associated mechanism during the downstroke of the pump and thus corresponds to Fig. 1 of the drawings except for the fact that in Fig. 1 the diameters of the various parts have been exaggerated and the differences in diameter between parts have been even more greatly exaggerated. In Fig. 7 low pressure or exhaust fluid (PL) is shown by dotted areas and high pressure or power fluid (PP) is indicated by xd areas.

Starting at the upper end of the balancing piston H5 in the valve head pocket 133 it will be seen that high pressure fluid (Pp) acts over the 'entire surface including annulus a.

At the W- er surface of the balancing piston H5 low pressure duid (PL) acts upon an annulus b` having the same area. The balance between the pressure on annulus a and annulus b thus is the area of the annulus a or b multiplied by the value (PP-PL) or the differential between the high pressure or power iluid and the low pressure or exhaust i'iuid.

The pressure diierential between the two types of fluid acting in a pump embodying the invention is the basis for allot the control of the valve body 6B and of the floating control collar l2 which exercises primary control over the valve body 60. It is by properly reacting to changes in the pressure differential between the two fluids and in the exposure of varying annular areas to these two fluids that motion of the valve body 6l) and, consequently,v valving of the two fluids is accomplished.

Continuing with Table I and Fig. 7, the next area to be considered is indicated as annulus c and is located on the upper surface of the main spool valve ltll in the clearance between the stepped shoulder 99 and beveled seat l'l on the valve casing $55 and the upper extension lfifi and upper beveled surface H36 on the spool valve lll. It should be noted that although these adjacent surfaces (shoulder 99 and extension m3 and seat l'l and surface lllii) are shown as meeting in Fig. l (because of the inability to show proper clearance in that figure), the surfaces do not actually contact each other and the clearance exaggerated therebetween in Fig. 7 actually exists in a structure embodying the invention. It should be noted that the sealino of the spool valve ll) at this point takes place between the step shoulder 98 on the casing 65 and the main cylindrical surface |02 of the spool valve lllil, these two surfaces being grounded with small 'tolerances.

This upper annulus c is subjected 'to lovT pressure fluid (PL) and the similar annulus d on the lower surface of the spool valve lill), i. e.,at` the beveled surface IM, is subjected to high pressure iuid (Pp). The pressure differential thus acting on the spool valve lll and, therefore, on the valve body 60 itself, equals the area of annulus c or annulus d multiplied by the value (PPuPL). This pressure differential however acts upwardly on the valve body El] by reason of the fact that the high pressure annulus d is on the underside of the spool valve loo in contrast to the pressure differential acting on annuli a and b which is downward on the spool valve body. In Table I upward pressure is indicated as -lvalue and downward pressure as value.

The next areas to be considered are those resulting from the offset in diameter of the valve body Sil created by the annular groove lo and opposed by the annular groove Bil in the collar 82. The location of annulus c at the lower end of the spool valve Hic or at the lower edge of the extension llll thereof, exposes the area of annulus e to high pressure fluid (PP). By reason of the connection through the conduit 35, the wall of the annular groove 'le in the'valve body 5l) is exposed to low pressure fluid (PL) as indicated at annulus f. The force acting on the-valve body 5! from annuli e and f thus is the product of the area of annulus e or f multiplied by the pressure differential value (PP-PL) and acts in an upward direction because the high pressure uid (Pp) acts on annulus e to push the valve body Gil upwardly.

As appears in the rightehand column of Table Labove, the balance of the pressure diierential acting on the six annuli above-identied results in there being a force totaling the pressure differential (PP-PL) times an area of .0238 square inch. This is suihcient force to hold the valve body ell upwardly with high pressure iiuid from the power fluid conduit lll) llowing in the path above indicated through the radial ports H3 to the central port 6l and then tothe upper end of the engine piston 4S.

The valve body El) remains in the position shown in Figs. l and 7 providing for the flow of high pressure or woiking'uid to the space above the'engine piston 49 land thus the downward movement of the engine `piston 49 and the pump piston' Z3, until the engine piston 4S reaches the bottom of its stroke, or until the pressure differential holding the control collar 'l2 in its upper position is otherwise removed, as by a racing stroke, as will later be described.

As the engine piston 49 approaches the bottom of its stroke its enlarged section 5l enters the sump 4l (Fig. 2). This'partially traps a small quantity oipower duid in'an annular space indicated by the reference number ll in Fig. 2. This small quantity of fluid is allowed to escape from the bottom of the engine cylinder i3 through the openings 45 only bypassing around the enlarged section 5l which has a 'small clearance with the interior of the axial walls of the sump lll. This small clearance Vprevents the enginev piston 3S from striking the bottom of the engine cylinder 43 sharply, the restricted escape orice for the oil trapped inthe space l3l slowing down the movement of the piston 49 and providing for the reversaloi the operation before the main body of the piston 49 reaches the bottom of the cylinder 43.

BOTTOM REVERSAL When the engine piston 49 approaches the bottom of its stroke the reduction of rate of flow of power fluid out of the engine cylinder i3 from the space beneath the piston'l also reduces the flow of oil upwardly past the rim 'l5 of the collar 12 and the unit pressuresactinglcn the collar 'I2 approach balance. AWhen the ow of oil past the collar 'l2 is sufficiently reduced so that the force acting upwardly on the collar 'l2 becomes less than the biasing force resulting from the area differential between the'ends of the collar l2, the collar '.2 is moved` downwardly. The biasing force is the force resulting from the fact that the diameter of the cylindrical section ill of the valve body 6o is lessthan the diameter of the cylindrical section ll of the valve body {il} and., therefore, the sum of the effective pressure receiving areas'of the upper end 83 of the collar l2, the beveled shoulder lll and the upper beveled shoulder of the rirn i5, is greater than the sum of the pressure receiving areas of the shoulder 'i3 and the lower beveled shoulder of the rim l.

The collar l2 is moved downwardly engaging its shoulder T13 against the opposed shoulder 'is on the cylindrical portion E555k of the valve body G. This drives the entire valve body Sil and its associated p-arts downwardly. As the valve body Si? moves downwardly the valving seal between the inner surface of the shoulder 93 and the cylindrical surface m2 of the spool valve lli is broken; the cylindrical portion 69 enters into valving engagement with the wall of the chamber @8; the `lower extension ld! of the-spool valve it@ enters the space dened by the annular interior of the lower shoulder 95. As soon as the valving surfaces 98 and |02 are broken low pressure fluid is admitted into the spool valve chamber `91 around the upper end of the main spool valve |00. Continued downward movement of the valve body then inserts the lower end of the main cylindrical surface |02 into the upper shoulder 95 at the lower side of the spool valve chamber 91'. The movement of the spool valve |00 downwardly to this position shuts off the flow of power fluid from the radial ports to the radial port ||3 into the interior bore 6| of the valve body 68.

A small quantity of fluid is, however, almost trapped in an annular space indicated by the reference number |38 in Fig. 4 between the beveled surface |04 and its Ibeveled seat |05. Because the outer surface of the extension |0| on the spool valve |00 is of lesser diameter than the inner surface of the shoulder 95, a thin annular orifice is left therebetween through which the uid trapped in the space |38 can slowly escape much in the samemanner as the fluid trapped in the space |31 beneath the engine piston 49 slowly escapes to prevent sharp engagement of the parts. The valve body 60 (and its associated mechanism) is thus slowly brought to a halt in its downward movement.

This same downward movement of the valve body 60 also inserts the cylindrical portion 69 of the valve body 60 into the enlarged chamber 68 above the lower pocket 51. This cuts off the axial slots 10 from the flow chamber 58.

Simultaneously with the just described operation, the downward movement of the spool valve E90 opens an annular passageway around its upper end, i. e., the stepped shoulders 98 and 99, connecting the exhaust chamber 81 with the spool valve chamber 91 and through the radial ports ||3 to the interior bore 6| of the valve body 60. f

This connects the engine cylinder 43 above the piston 49 to the exhaust chamber 81 and through the radial openings 88 to the exhaust duct 89 and the radial port 90 to the production fluid annulus 36. This connection results in dropping the pressure of the fluid above the engine piston 49 to the lower pressure existing in the production and exhaust fluid annulus |36.

Because the power fluid remains connected to the space |31 beneath the engine piston 49, i. e., because the collar 12 does not act as a valve with respect to its cooperating land 16, high pressure power fluid beneath the engine piston 49 now is exerted against the lower pressure fluid above the engine piston 49 that is connected only to the low pressure production and exhaust fluid annulus |36. Therefore, the engine piston 49 is moved upwardly.

As the engine piston 49 starts to move upward under the pressure of the power fluid being forced into the space |31 beneath it, the pump piston 2S also begins to move upwardly which causes the travelling ball valve 31 to be seated and the standing ball valve 38 to be opened. This draws production fluid into the pump cylinder 22 beneath the pump piston 28 as it moves upwardly and exhausts or discharges the production fluid in the pump cylinder 22 above the pump piston into the production fluid conduit 4| and eventually into the production fluid annulus |36 and to the surface.

UPSTROKE As soon as the lower edge of the main spool valve surface |02 has entered the sealing surface of the upper shoulder 96, the balance of hydraulic Table II.-Pressure acting on valve during upstroke (See Figs. 5 and 8) Effective Area in On Part s Number Fluid Acting Direction Balance Sq. Inches Low.

Down -.0468 (Pp-Pi.)

Referring particularly to Figs. 5 and 8, it will be seen that all of the cross sectional areas of the valve body 60 and its associated parts are balanced out except for the two annuli indicated as g and h in Fig. 8. These other areas balance as follows: The top area of the balancing piston 5 having a diameter D is balanced by the lower end of the valve body 50 at its greatest diameter D at the cylindrical portion 69. Both of these areas are exposed to low pressure exhaust fluid.

The lower surface of the balancing piston I5 out to the diameter of the main cylindrical surface |02 of the spool valve |00 (i. e., the diameter C) is balanced against the upper surface of the spool valve |00. Both of these areas are exposed to low pressure fluid, thus leaving the annulus g (diameter D minus diameter C) unbalanced and subject to low pressure fluid acting upwardly. The area of this annulus g is .0468 square inch on a pump having the dimensions set forth above with respect to Table I. The annulus g is the first unbalanced area which must be considered and thus appears on line l of Table II above.

Similarly, the lower surface of the spool valve |00 to the maximum diameter of its main cylindrical surface |02 is balanced against an area extending to an equal diameter C on the upper surface of the collar 12. These two surfaces are exposed to high pressure uid in the upper part o-f the flow chamber 58. Because the collar 12 is fully seated with its shoulder 13 against a mated shoulder 14 on the spool valve body 60, the collar 12 in the position illustrated in Figs. 5 and 8 is, in effect, a fixed part of the valve body 60.

The area of the collar 12 in excess of diameter C is balanced both above and below by high pressure fluid in the flow chamber 58.

At the meeting corner of the shoulder 14 on the cylindrical portion 69 of the valve body 60 and the outer surface of the cylindrical portion 69 itself, i. e., just beneath the rim 15 of the collar 12, an annulus h having an area determined by the diameter D minus the diameter C, is exposed to high pressure fluid in the chamber 58. This fluid acts downwardly. The annulus h, is the second unbalanced area on the valve body 60 in the position shown in Figs. 5 and 8, i. e., during the upstroke of the engine piston, is equal to the area of the annulus g or h, multiplied by the pressure differential (PPeFL). This This force acts downwardly as shown in Table II above.

This condition continues during the upstroke of the engine piston and holds the valve in the position indicated in Figs. and 8, with the power fluid flowing downwardly through the ilow chamber 58 to the lower end of the engine piston 49 and the exhaust fluid being displaced upwardly through the axial bore El in the valve body 6E! to the spool valve chamber 9"! and out ythrough the exhaust duct 89.

This movement continues until the engine piston approaches the upper limit of its stroke at which time the cylindrical extension 52 on the engine piston 49 enters the pocket 48 at the upper end of the engine cylinder 13 reaching the position shown in Fig. 6.

Tor REVERSAL As the cylindrical extension 52 enters the upper pocket 48 of the engine cylinder 6.15, the pressure on the fluid now trapped in an annular space indicated by the reference number its in Fig. 6 increases. The duid trapped in the space l39 can escape therefrom only through the relatively small clearance around the exterior of the extension 52 of the piston 49 or through the axial passageways 56 which lead upwardly 'to the lower pocket' El. This increase in. pressure on the lower end of the valve stem 55 and on the walls of the axial slots 'lil and in the interior of the axial bore (il of the valve body 60 raises the valve body Gl) and its associated parts` before the end of the extension 52 of the piston 4Q contacts the lower end of the valve stem 55.

The spacing of the parts is such that the rim l5 of the collar 'l2 laps the land 'FEB before the spool valve |053 is moved out of its cylindrical seat, i. e., before the main cylindrical surface HB2 is unsealed from the shoulder 96.

As soon as the rim 'l5 of the collar l2 laps its land 76, the volume of the flow of power fluid past the rim 'l5 and into the now chamber 5B thence to the lower end of the pump cylinder d3, is substantially reduced and the upwardly movement of the piston 49 is slowed.

As soon as the spool valve liil is moved upwardly a distance sufficient 'to unseal its main cylindrical surface W2 from the upper shoulder 9B, high pressure fluid immediately flows through the spool. Valve chamber 91 and radial port H3 into the interior bore iii of the fvalve body 6l! and into the upper end of the engine cylinder 43. This reverses the movement oi' the engine piston i8 starting it down.

As high pressure power duid enters the axial bore 6| it also flows upwardly through that bore to the angularly drilled orices t2 where it is trapped in the space i3d by the valve head 64. As the valve body Gli continues to move upwardly by reason of the high pressure on the lower faces of the several sections, the lip 529 on the check sleeve |25 strikes the shoulder |32 at the edge of the valve head pocket |33 and the upward movement of the check sleeve |26 is stopped. As the valve body 6l] and the `valve head 64 continue to move upwardly the seal between the seat |30 and the beveled ycorner |3| is broken. This allows high pressure power iluid to flow into the .fvalve head pocket |33 and to act on the upper surfaces of the check sleeve |26 moving it down. The lower lip |22 of the ring I2i caps ou the. upper open ends of the connecting slots i9 which, through the bleeder holes l I8, communicate with the exhaust chamber Hl beneath the balancing piston |5. Further downward movement of the check sleeve |25 moves its lower lip |21 into the space just above the disk-like flange. |20 sealing off the bleeder openings |35.

Although the bleeder openings |35 were open at the time of the commencement of the top reversal (as shown in Fig. 6), and remain open duringv the initial entry of high pressure lluid from the orices t2 into the chamber lll, the initial downward movement of the check sleeve |26 brings its lower edge lli'l closely adjacent the ring |2| above the bleeder openings |35. Therefore, uid tending to flow out through the bleeder openings |35 must pass the restricted annular space thus formed. There is thus a lower pressure on the underside of the check sleeve lip |2l than is exerted on the top of the check sleeve so that the sleeve will continue to move down into full seating engagement against the disk-like iiange Wil closing off the bleeder openings |35 and trapping hig-h pressure iluid above the balancing piston l5.

The upward movement of the valve body Si! and its operatively associated parts, although initiated before the engine piston il@ reaches the upper limit of its travel, is not completed until after the engine piston t9 has already travelled a substantial distance downwardly and it may, in fact, not be completed until the engine piston a9 appreaches the bottom of its stroke.

Low pressure fluid is trapped during the previously described upward movement of the valve body lill and spool valve mil in a space designated by the number |49 in Fig. 6 between the upper beveled surface |06 of the spool Valve ii and its beveled seat |07. The fluid in 'the space |40 acts as a cushion for the valve body 5? and prevents any pounding at the end of the upward movement because such fluid must escape around the relatively small opening between the cylindrical upper extension |l'3 of the spool valve it@ and the shoulder 99 with which it cooperates.

As soon as the check sleeve chamber lll and the valve head pocket |33 are illed with high pressure fluid, the mechanism nally comes to restin the position illustrated in Fig. 1. Again the flow of high pressure fluid out of the engine cylinder it from the space beneath the downwardly moving engine piston le past the rim 'l5 of the collar l2 causes that collar to float in the dow chamber 58 in the position shown in Fig. l. In this position of the collar 72 which continues during the downstroke of the device, there is formed a relatively constant orice around the periphery of the lip 'l5 with the wall of the ow chamber 53 in series with a variable orice formed by the upper shoulder 9| of the collar l2 and its opposing stationary shoulder S2.

The presence of the high pressure oil above the valve head 64 reduces the otherwise overwhelming. upward thrust of the power iiuid acting through the axial bore 6l of the valve body 5i) and balances the valve system so as to permit the movement of the Valve to the position shown in Fig. fi at the bottom reversal of the device by the force available from the control collar l2.

EFFECT or GAS IN PUMP Cuisiner.

Because of the presence of gas pockets in connection with oil pools, gas itself frequently is drawn into the pump cylinder of -a downwell pump. When this occurs in a downwell pump embodying the invention on the upstroke of the pump, the gas enters the pump cylinder 22 beneath the pump piston 28 and may, in fact, entirely ll the cylinder 22 beneath the piston.

Upon the next reversal of the pump, i. e., upon the commencement of a subsequent downstroke of the engine piston 49 and pump piston 28, the

gas drawn into the pump cylinder 22 offers but little resistance to the downward movement of the piston 28 due to its compressibility. Since there is no liquid in the pump cylinder, the traveling valve 3l' remains seated and the static head from the production column acts through passage 3d, passages 33 and the center passage 32 on the pump piston in a downward direction. This added energy causes the engine piston 49 to start to move downwardly at a high rate of speed. This exerts excessive pressure on the fluid in the engine cylinder 43 beneath the engine piston t9 and forces it upwardly through the annular conduit 44 under higher pressure than would normally be present.

The fluid thus is forced upwardly through the flow chamber 58 under pressure higher than it has when it reaches that position during a normal stroke with the engine piston 49 moving downwardly under load. The increased pressure in the fluid in the flow chamber 58 further increases the forces acting upwardly against the control collar l2. Because the pressure in the oil in the chamber 58 beneath the control collar 'i2 is proportionately higher than the pressure in the chamber 58 above the control collar 12, the pressure drop around the rim 'l5 of the control collar being thus greater, the collar 12 is moved upwardly.

When the control collar 12 is moved upwardly its beveled shoulder 9| approaches the beveled shoulder S2 on the lip 93, restricting the annular passageway normally existing therebetween (most clearly seen in Fig. 7) The reduction in area of the passageway between the cooperating shoulders S2 and 93 restricts the flow of iluid out of the flow chamber 58 and thus out of the lower end of the engine cylinder and thus limits the rate at which the engine piston can move down. When the engine piston has slowed down, the pressure above the flow collar 12 may again approach the normal operating differential with respect to the pressure acting beneath the collar l2. When this condition is achieved, the collar l2 moves downwardly by reason of the greater effective area on its upper end due to the offset in the diameter of the valve body 60 on which it slides (Fig. '7, diameter A minus diameter B).

rThe return of normal pressure balance in the pressures in the ilow chamber 58 results in returning the collar 'l2 toward its normal lower position as illustrated in Fig. 7. In effect, therefore, when gas is present beneath the pump piston 28 and the pump enters what would otherwise be an excessively high speed stroke, the effect of the presence of the gas is to increase the pressure on th iluid beneath the engine piston 49, to raise the floating control collar 'l2 above its normal position in the ilow chamber 58, and to cause it to exercise a throttling or governing effect on the rate of movement of the engine piston 49,.

maintaining the speed of the piston 49 at substantially its normal rate.

In the event that the engine piston 49 should start downwardly with such a high rate of speed' that the pressure in the iluid beneath the piston i9 increasesto such an extent that the iloating control collar 'l2 is thrust upwardly until its beveled shoulder 9i comes into contact with the cooperating beveled shoulder 92, the flow of expelled fluid from beneath the engine cylinder 49 would be stopped completely and the engine piston d8, and thus the pump, would lock up, were it not for the presence of the axial bleeder passageway H2 (Fig. 7) which communicates between the flow chamber 58 and the power lluid conduit H0. The bleeder passageway H2 allows enough fluid to pass from the high pressure area in the ilow chamber 58 to the lower pressure in the power iluid conduit H0 to release the control collar 'l2 from its upper position and carry it into its balanced iloating position explained above.

The likelihood of ythe existence of conditions conducive to a high speed up-stroke is very much less than the likelihood of the conditions described above which would give rise to a high speed down-stroke. This is due to the fact that there is always present in the production column the liquid exhausted from the engine cylinder which would act as a static head even when no liquid was being pumped from the formation. However, in the event that gas does become trapped above the pump piston 23, the resistance to the movement of the pump piston 28 upwardly is lowered only by the compressibility of the gas and by the reduction in the total weight of the static head of production and exhaust iluid resulting from the gas therein. Under these conditions the engine piston 49 has a tendency to make up an upward stroke at an increased rate of speed. This rapidity of movement increases the pressure of the fluid above the engine piston i9 very rapidly and to a higher level than normally would exist. Because the fluid above the engine piston 49 must discharge upwardly through the bore 6I in the valve body 60 (Fig. 8) and is partially trapped in the pocket 48 and the enlarged chamber G8 beneath the cylindrical portion 59 of the valve body 68, increase in pressure therein raises the valve body 60 slightly. This reaction results from the fact that the pressure differential in the iluid in the top of the engine cylinder and in the partially gas illled production column is increased by the flow through the bore 6I, and the radial ports H3. The several passages therefore become restricting orilces for the iluid thus being rapidly expelled.

Because the balance of forces acting to hold the valve body 69 downwardly in the position shown in Fig. 8 (see Table II above) is only slight, the increase in pressure, particularly where it acts through the radial ports H3, overcomes the balance and the valve body 60 .moves upwardly.

As soon as the valve body 60 starts to move upwardly the collar 12 is moved upwardly with it and the rim 15 of the collar 12 approaches the land '55. This narrows the annular opening between the rim 15 and land 15 and restricts the ilow of power fluid downwardly through the annular conduit 44 to the interior of the engine cylinder 43 beneath the engine piston 49. Restriction of the low of fluid to the space beneath the engine piston 49 slows its rate of upward movement. When the collar 'i2 moves into association with land 16, a pressure drop across the nose of the collar will be established tending to urge the collar and valve downwardly and tends to prevent a complete reversal of the valve.

At the same time, and providing that the valve body 50 has been thrust upwardly a suilicient distance, the upper extension |03 on the spool valve |88 extends into the area delineated by the step shoulder 99 (Fig. 8) and reduces the flow of exhaust fluid between chambers 91 and 81 even further. This increases the pressure in the exhaust fluid side of the line commensurate with the reduction in pressure on the power fluid side of the system. This action, and the action aesazw El of collar l2, continues to tend to restore the normal pressure balance.

As a result of the metering or throttling action of the upward movement of the valve body lili carrying the rim into closer proximity with the land during the movement of the engine piston upwardly with gas in the production column the valve body Sil is lifted from its sea-t (i. e., the position shown in Fig. 8) and floats at a higher level where it, acting in response to the balancing of forces exerted by the control collar lil, throttles the rate of movement of the engine vpiston 49 preventing it from racing when gas is present during the upstroke and thus controlling its speed within relatively narrow limits.

SPEED GOVERNING The rate of piston travel of a pump embodying the invention is primarily determined by the quantity of the actuating power iiuid supplied thereto and is goverened at the determined speed by the iioating collar 'l2 under normal stroking conditions.

As is explained above in the section entitled Downstrolre (Fig. '1) fluid forced from beneath the engine piston 69 during a downstroke flows up the annular conduit del into the flow chani r' passing the rim 'l5 of the collar l2. The perimeter of the rim 'l5 is spaced inwardly from the cylindrical surface 'i8 of the chamber it?. forming a constant annular orifice through which the expelled fluid must flow on route to the variable orifice at the upper end oi the collar l2 and the intersection with the stream of power huid flowing out of the radial ports i i l.

The constant oriiice formed between the rim le and the wall is of the flow chamber controls the normal speed of operation and such speed is only modified in exceptional instances by the action of the variable orice to reduce the rate of flow through the iiow chamber 58. When a build up in pressure beneath the rim l5 of the collar 'l2 which might otherwise increase the velocity of the fluid flowing past the rim 15 and allow the speed of movement of the engine piston #le to increase takes place, the action of the collar lil explained above in decreasing the variable oriiice prevents the increase in velocity and consequent increase in speed of operation.

Speed governing and control during the upstrolre of the engine piston d@ in normal operation also is established by the volume of the power fluid. Even under slightly abnormal conditions, i. e., where a quantity of gas has entered the pump, the relative constancy or" the static head of the production uid in the production fluid annulus I3@ will. serve to maintain a substantially constant upstroke velocity. The weight of the column of production fluid extending to the surface is so great with respect to the small variation in the amount of gas usually encountered that no appreciable change in its load against the pump occurs. Under some conditions, however, the volume of gas encountered in the pump operation may be so large as to fill a substantial length of the production fluid column, in which case the static head against which the pump is working is reduced and the floating collar l2 must be relied on to govern the maximum speed of operation as explained above.

Normal speed control during the upstroke is a function of the pressure and volume of the working fluid and the annular space existing between the uppermost edge of the rim 15 of the collar 'l2 and the land 'I6 (Fig. S). As explained above with respect to operation in the presence of gas, if the engine piston et for some reason is urged upwardly at a rate of travel higher than that desired, the valve body 6B and thus the iloating collar l2 move upwardly to throttle ofi the flow of power huid from the flow chamber 58 downwardly past the land IEV and rim it.

Thus speed governing is effective and rate of operation substantially constant whether the pump is handling oil alone, or mixtures of oil and gas such as frequently are encountered in a well. The positioning of the floating collar 'i2 in a path through which iiuid must either flow or be expelled during the operation of a pump embodying the invention `results in there being always present an element immediately responsive to changes in the pressure of the iiuid passing thereby which might be caused by changes in viscosity of either the power oil or the production fluid, or the presence of lighter fluid such as gas, or other changes in the viscosity or pressures of the fluids being handled. |The balancing effect of the floating collar 'l2 is such that these changes have little elfect on the overall speed in number of strokes per minute of a pump embodying the invention.

In general, therefore, control of the speed of operation of a downwell pump embodying the invention is readily adjusted by altering the pressure and volume of the power fluid supplied since the orices through which the pressure fluid and production fluid must pass are constants. It is possible to achieve a substantial range in nurnber of strokes per minute in any particular pump SUMMARY es explained above, by reason of the fact that all of the valving operations of a pump embodying the invention are caused by changes in pressure and by relative pressures acting on the iioating control collar l? and the elements of the valve body 6, and because there is, therefore, no mechanical connection necessary between the engine piston its or its cylinder i3 there is no need for a positive mechanical or structural connection between the assemblies. Although in the modification of the invention illustrated in the drawings, the valve casing 65 is shown as` being structurally integral with the engine casing 42 such integrity or even its proximity is not necessary. The structures may be separated from each other at the level of the axial bore 5d and the only connections between the valve casing te and engine casing 52 necessary would be pipes or conduits corresponding to the production iiuid conduit all, annular conduit fili, passageways 't and pocket 4t.

Similarly, because the engine piston Q9 maires no mechanical connection with the valving mechanism a standard valving mechanism can be employed with engine pistons Si and pump pistons 28 having any desirable length of stroke.

Having described my invention and a particular embodiment thereof herein in which a modied single action pump portion is employed for the purpose of actually moving the production fluid from the well to the surface, it is to be understood that the invention herein disclosed is not limited to the particular pump structure or the particular details of the valving or other struc- 22% ture but is encompassed within the following claims.

What I claim is:

l. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump Cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising valve means to direct the flow and release of operating fluid to said engine cylinder, said valve means including a differential area flow rate control and valve shifting collar subject to the pressure of operating fluid on its larger area and to the pressure of fluid exerted against the smaller area of said engine piston on its smaller area.

2. In a fluid operated downwell pump com prising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising a single valve movable in one direction to cause flow of operating fluid to the larger area of said engine piston, and means movable relative to said valve and responsive to the pressure in said engine cylinder to move said single valve in the opposite direction to cause flow of operating fluid to the smaller area of said engine piston.

3. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereon in one direction, and a source of operating fluid under pressure, the improvement comprising a valve movable in one direction to cause flow of operating fluid to the larger area of said engine piston, a differential area valve shifting collar associated with said valve and operable when the pressures on its faces are balanced to move said valve in the other direction to cause release of operating fluid from the large area of said engine piston.

4. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereon in one direction, and a source of operating fluid under pressure, the improvement comprising a valve movable in one direction to cause flow of operating fluid to the larger area of said engine piston, a differential area valve shifting collar associated with said valve and operable when the pressures on its faces are balanced to move said valve in the other direction to cause release of operating fluid from the large area of said engine piston, and means on said collar to control the rate of flow of fluid to and from at least one end of said engine piston.

5. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising a main tubular valve movable in one direction by pressure of fluid escaping from said engine cylinder to cause flow of operating fluid to the larger area of said engine piston, a differential area flow rate control and valve shifting collar carried by said main tubular valve and reciprocable relative thereto, means on said main Valve to limit the movement of said collar in one direction, said collar having differential area faces whereby, when the pressure on its faces are balanced said collar is biased in a direction tending to engage said means and to shift said main valve in a direction opposite to that in which said main valve is moved by said engine cylinder pressure.

6. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising a main tubular valve shiftable by hydraulic pressure from said engine cylinder to one position to cause flow of operating fluid to the larger area of said engine piston, a differential area flow rate control and valve shifting collar carried by said tubular main valve and reciprocable relative thereto, an enlargement on said main valve to limit the movement of said collar in one direction, said collar having differential area faces whereby, when the pressure on its faces are balanced said collar is biased in a direction tending to shift said main valve to a position opposite to that to which said main valve is moved by the engine cylinder pressure, a flow chamber through which fluid passes from the smaller area of said engine piston, the pressure of said fluid being exerted against the smaller area of said collar and tending to move said collar away from said enlargement, and a variable orifice formed by said collar and portions of the walls of said flow chamber in the path of movement of said collar and adapted to restrict said chamber and thereby reduce the fluid flow therethrough, whenever the pressure .against the smaller area of said collar exceeds the pressure on the larger area thereof by a predetermined amount.

'7. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising a main tubular valve adapted, in a first position, to open communication between said source of fluid pressure and the engine cylinder portion above the larger area of said engine piston, and in a second position to open communication between said engine cylinder portion and a discharge passage at relatively low pressure, and means subject to supply pressure on one face and to the pressure on the smaller area of said engine piston on another face to move said valve to said second position, said last means having diiferential areas the larger of'which is exposed to said supply pressure.

8. In a duid operated downwell pump cornprising a pump cylinder, an engine cylinder longitudin'ally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising a main tubular valve movable in one direction by pressure of fluid escaping from said engine cylinder to cause flow of operating fluid to the larger area of said engine piston, said valve including a stem extending therefrom, a shoulder on said stem intermediate its ends, a rate control and valve shifting collar having an upper portion closely tting said stem above said shoulder and a lower portion closely fitting said stem below said shoulder, said collar having an internal relieved zone on each side of said shoulder whereby said collar is reciprocable on said stem, means to maintain said relieved zone at a pressure lower than the pressure of said operating fluid, and means on said main valve to limit the movement of said collar in one direction.

9. A iiow directing and control means for a hydraulic engine having an engine cylinder, and an engine piston in said cylinder, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, comprising a valve housing having spaced valve forming parts, a pressure fluid conduit and an escape conduit leading to,

said housing, a duct leading to one end of said engine cylindery a reciprocable valve body having parts cooperating with said valve forming parts for alternatively connecting said pressure and escape conduits to said duct, a passageway from said pressure fluid conduit that is constantly in communication with the other end of said engine cylinder and includes a flow chamber surrounding a portion of said valve body, a control collar reciprocable on said valve body within said flow chamber, said control collar having a greater effective area on one end than on the other whereby uniform pressure in said flow chamber biases said control collar in one direction, and means on said valve body against which said collar exerts its bias for urging said valve body into a position for connecting said escape conduit to said duct.

10. The combination of means defined in claim 9, and means on said control collar disposed in said passageway to govern the rate of flow of iluid through said iiow chamber.

ll. The combination of means defined in claim 9 in which said control collar is disposed in an upper normal position when said valve body connects said pressure fluid conduit and said flow chamber, and in a lower normal position when said valve body connects said pressure iiuid conduit and said duct, a land on said flow chamber wall intermediate its ends, and a cooperating surface on said control collar, said land being so disposed as to cooperate with said surface 26 when said control collar is moved opposite thereto to restrict the ow of operating fluid to the lower end or said engine cylinder.

12. The combination of means dened in claim 9 and a balancing member connected to said valve body, said balancing member being subject to the pressure of said escape conduit on one side and alternately to the pressure of said escape and pressure conduits on its opposite side whereby to assist in establishing biasing hydraulic forces on said valve body to maintain said valve body in its reciprocated position.

13. A flow directing and control means for a hydraulic engine having an engine cylinder, and an engine piston. in said cylinder, said engine piston having a greater eifective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, a valve housing having spaced valve forming parts, a pressure fluid conduit and an escape conduit leading to said housing, a duct leading to one end of said engine cylinder, a reciprocable valve body having parts cooperating with said valve forming parts for alternatively connecting said pressure and escape conduits to said duct, a passageway between said pressure fluid conduit and the other end of said engine cylinder and including a flow chamber surrounding a portion of said valve body, a control. collar reciprocable on said valve body Within said ow chamber, cooperating surfaces including a surface on said collar forming a variable orifice for varying the flow through said flow chamber inversely to the pressure of fluid against the smaller area of said engine piston, said collar having a greater effective area on one end than on the other whereby uniform pressure in said flow chamber biases said control collar for movement in a direction to open said variable orifice, and high pressure on the smaller effective area of said control collar overcomes the bias `and moves said control collar in a direction to reduce said variable orifice, and means on said valve body against which said collar exerts its bias for urging said valve body into position for connecting said escape conduit to said duct.

14. A flow directing and control means for a hydraulic engine having an engine cylinder, and an engine piston in said cylinder, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, a valve housing having spaced valve forming parts, a pressure uid conduit and an escape conduit leading to said housing, a duct leading to one end of said engine cylinder, a reciprocable valve body having parts cooperating with said valve forming parts for alternatively connecting said pressure and escape ccnduits to said duct, a passageway between said pressure fluid conduit and the other end of said engine cylinder and including a flow chamber surrounding a portion of said valve body, a control collar reciprocable on said valve body within said flow chamber, cooperating surfaces, including a surface on said collar forming a constant orifice connecting said iiow chamber with the other end of said engine cylinder and establishing a normal rate of flow of iiuid through said flow chamber, other cooperating surfaces, including a surface on said collar forming a variable orice in said flow chamber and establishing a maximum rate of iiow through said flow chamber, said collar having a greater effective area on one end than on the other whereby uni- 27 form pressure in said flow chamber biases said control collar for movement in a direction tending to open said variable orifice, and high pressure on the smaller effective area of said control collar overcomes the bias and moves said control collar in a direction to reduce said variable orifice and means on said valve body against which said collar exerts its bias for urging said valve body into position for connecting said escape conduit to said duct.

15. A flow directing and control means for a hydraulic engine having an engine cylinder, and an engine piston in said cylinder, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, a valve housing having spaced valve forming parts, a pressure fluid conduit and an escape conduit leading to said housing, a duct leading to one end of said engine cylinder, a

reciprocable Valve body having parts cooperating with said valve forming parts for alternatively connecting said pressure and escape conduits to said duct, a passageway between said pressure fluid conduit and the other end of said engine cylinder and including a flow chamber surrounding a portion of said valve body, a flow control collar reciprocable on said valve body within said flow chamber, cooperating surfaces, including a surface on said collar forming a constant orifice connecting said flow chamber with the other end of said engine cylinder and establishing a normal rate of flow of fluid through said flow chamber, other cooperating surfaces including a surface on said collar forming a variable orifice in series with said constant orifice, said passageway and the other end of said engine cylinder to reduce the flow through said flow chamber and ccnstant orice in response to an increase in pressure of fluid against the smaller area of said engine piston, said collar having a greater effective area on one end than on the other whereby uniform pressure in said flow chamber biases said flow control collar for movement in a direction to open said variable orifice, and high pressure on the smaller effective area of said control collar overcomes the bias and moves said control collar in a direction to reduce said variable orice and means on said valve body against which said collar exerts its bias for urging said valve body into position for connecting said; escape conduit to said duct.

16. A ow directing and control means for a hydraulic engine having an engine cylinder, and an engine piston in said cylinder, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, a valve housing having spaced valve forming parts, a pressure fluid conduit and an escape conduit leading to said housing, a duct leading to one end of said engine cylinder, a reciprocable valve body having parts cooperating with said valve forming parts for alternatively connecting said pressure and escape conduits to said duct, a passageway between said pressure fluid conduit and the other end of said engine cylinder and including a flow chamber surrounding a portion of said valve body, a control collar reciprocable on said valve body within said flow chamber, cooperating surfaces on said collar and on the walls of said flow chamber forming a constant orifice connecting said chamber with the other end of said engine cylinder and establishing a normal rate of flow of fluid through said flow chamber, cooperating valving surfaces on said collar and on the walls of said flow chamber forming a variable orifice in seriesbetween said constant orifice and the pressure fluid end of said passageway, said collar having a greater effective area on one end than on the other whereby uniform pressure in said flow chamber biases said control collar for movement in a direction to open said variable orifice, and high pressure on the smaller effective area of said control collar overcomes the bias and moves said control collar in a direction to reduce said variable orifice and means on said valve body against which said collar exerts its bias for urging said valve body into position for connecting said escape conduit to said duct.

17. In a fluid operated downwell pump comprising a pump cylinder, an engine cylinder longitudinally displaced from said pump cylinder, connected pistons operating in the respective pump and engine cylinders, said engine piston having a greater effective area on one side than on the other whereby equal operating pressures on its two faces cause movement thereof in one direction, and a source of operating fluid under pressure, the improvement comprising valve means to direct the flow and release of operating fluid to said engine cylinder, said valve means including a differential area collar subject to the pressure of operating fluid on its larger area and to the pressure of fluid exerted against the smaller area of said engine piston on its smaller area.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 245,777 Brazelle Aug. 16, 1881 539,339 Breitenstein May 14, 1895 2,195,208 Cornelius Mar. 26, 1940 

